1. Field of the Invention
The present invention relates to a photographic camera system including a main camera body and an electronic flash device detachably attached to the main camera body, and more particularly to a start control of the system.
2. Description of the Prior Art
With an increasing systematization of the photographic camera in recent years, the photographic camera and the electronic flash device are more and more closely interconnected with each other. For instance, a U.S. patent application published under U.S. Pat. No. 4,436,396 teaches a photographic camera system in which when the camera is supplied with power from a battery incorporated in the camera a signal indicating the power supply to the camera is provided to the electronic flash device and based on this signal power is supplied also from a flash battery incorporated in the electronic flash device to circuits of the electronic flash device whereby the flash device starts preparatory operation for a flash photography. That is to say, according to this known photographic camera system, the power supply indicating signal is used as a trigger signal for starting, e.g. a voltage boosting circuit including in the electronic flash device and the preparatory operation for a flash photography is started simultaneously with the power supply to the camera. In practice, however, a flash photography is not necessarily carried out when the electronic flash device is attached to the camera. Therefore, according to the above-described start control for a photographic camera system, when the flash photography is not carried out, the battery power used for the preparatory operation of the electronic flash device is only wasted.
There is another known photographic camera system in which a unidirectional or bidirectional information transfer is carried out between the camera and the electronic flash device whereby based on the information predetermined flash photography data are calculated. According to this system also, the aforementioned problem occurs as long as the electronic flash device, i.e. the preparatory operation is started simultaneously with the power supply to the camera.